Torpedo defense and the like

ABSTRACT

581,361. Controlling apparatus by sounds. O&#39;DWYER, D. M. Dec. 30, 1941, No. 16778. [Class 118 (ii)] Relates to a method of destroying hostile torpedoes or other objectives that emit sounds during use. According to the invention, a defending torpedo or other craft is steered automatically into contact with the hostile torpedo, the steering of the defending torpedo being controlled by a selective device which distinguishes the characteristic sounds of the hostile torpedo from otlier sounds and converts the selected sound waves into fluctuations of light which effect the steering control. The apparatus may consist of two microphones 7, 8, Fig. 1, mounted in the head 9 of the defending torpedo on opposite sides of the longitudinal axis. Each microphone is . connected to an amplifier 10 which controls the light emitted by an electric lamp 12 or 13, so that fluctuations of the sounds received by the microphones cause fluctuations of the light emitted by the lamps. The light from the lamps passes through inclined passages a, b in a &#34;gate&#34; 16 which has another passage c through which a cinematograph film 19 can be drawn past the crossing of the passages a, b. The light from the lamps 12, 13 falls on photoelectric cells 14, 15 respectively, which are connected in series with a battery k and a pair of relay coils 2, 3. which operate the steering control 5. The coils are connected with two other relay coils 20, 20a. The cinematograph film 19 is printed with a sound track, shown in Fig. 2, corresponding to the sound emitted by a hostile torpedo. The film is driven by a motor 18 through a clutch which is controlled by the relay coils 20, 20a. In use, the maximum amount of light from a lamp 12 or 13 is received by the co-operating photo-electric cell when the markings on the film are in synchronism with the fluctuations of the light from the lamp. When this occurs, the relays 2, 3 will control the steering until the amount of light received by each cell is equal, and the torpedo is then directed straight towards the hostile torpedo. The control of the clutch 21 by the cells 14, 15 through the coils 20, 20a serves to vary the speed of the film 19 through the gate 16 so that it tends to keep the film markings in synchronism with the variations of the light from the lamps 12, 13.

Feb. 26, 1946. 1 D. M. O'DWYER 2,395,422

TORPEDO DEFENSE AND THE LIKE Filed Jan. 11, 1943 SYSTEM SYSTEM AMPUFYING AMPLIFYING MICROPHONE MICROPHONE Patented Feb. 26, 1946 UNITE-1i.

STATES PATENT OFF CB Application-January 1'1, 1943;-Seri-alrNo.;4-72,04 6 'In Great Britain Decemberw30 1941 2 Claims. 7. (Cl. 114- 23) This .inventiom relates to torpedo z'defense and thelikerithat is to sayylto the-defense of battle-1 1 ships;or craft or istationarylobjects against attaclrsibyzhostile torpedoes; byrsubmarines or by other craft. (1

Referring to the accompanying: diagrammatic.

drawing Figure "1 illustrates an arrangement according to one form of thexpresent invention employing twox microphones; and.

Figurerzis' adiagramnratic: view of a film track.

Inl-carryingthe invention into effec'twin one form' by'way of example in general terms, a de fensentorpedouis constructed :with two or 'more sound @receivingidevices: Whichxrnayrr picki'up.

sounds "of awide "range provideditheyr within that range :are; ieapable; of accepting: sounds .1 made ;..by the passages of a. particular-selected oncoming torpedo throughythe water. The known" sounds.

thus picked up are caused by any suitable mecha= nism -to produce light waves or waves'or impulses or to modify theaction of a sourceor sources of illumination. .Thelightfpasses through a light gate similarto the sound track on a preformed cinematograph: talking mm, "the sound to which thertrackcorresponds being ithatcof the passage of the selected torpedo through. the water. This track .is drivenat an appropriate .speed which may-be VariabIeLLWhen the speed is suchthat the:soun'd of the oncoming hostile torpedo corremaintained-r The: light." passing through this trap 'or gateifalls on to a selenium cell or the like andcthus modifiesa local circuit which operates theirudcler or lother steeringdevice of the torpedozrrr A constructionalirarrangementon the above linesis illustrated inFigures 'l and 2 wherein two' microphones 1.; 8 are fixed at "'an 'angleto the longitudinal axis in thenose 9 of a torpedo. The microphones are connected r to amplifying systems: Ml, H which control respectively light emitted by neonilampslz, l3; the microphones are of anyssuitable kind, e. g., carbon microphones.

Each: microphone is in electrical circuit with a separate battery and" this circuit includes the primary of astep up transformer mot shown) of such' a nature thatithe secondary circuit'hasa sufiiciently high voltage to'operatethe neon lamps; The lamps-need not" necessarily contain neontgas;:any=gas suitable for the" purpose of the invention couldbeused; The: electrical vvaria-P-n tions in "the primaryacircuit of-the transformer :1 cause corresponding variations-in the luminosity of the neon lamps. If necessary the light in the-n r neon lamps may be increased lay-employing valves 1 r and accessory batteries- The'light from eachof the neonlamps-is concentrated on the film by a condenser and-objec tive lens (not shown): The condenser 'lensare adjacent to the respective lampsvand the objective lens adjacent to the film. Between each'pairsof lens a narrow slit is placed rThelight fromthe lamp-is made to'converge -on the slitsr by -the condensers --and the diverging rays passing. through'the slit are, collectedby'the objective lens. 1 and-'concentratedion theifilm so that images of the slits are formed on the: film.

Light-sensitive cells. 14 "and" ii are provided,- passage of light from the'li'ght sourcesto thecells taking place by way of a gate li a-Selenium cells may be substituted for photocells since ithetfunc= tionof the photo cells is not to reproduce minute electrical variations but to register certain gross-.r changes in the. amount. of light passing through the film; -The photo-sensitive cells are in an electrical circuit associated with onewhich-oper-v ates a pair of solenoids 2, 3, co-operating with an" armature I 1 pivoted at '4. Connected in parallel" I with the coils 2; 3 aretworelaycoils 20,-2Ua."-=As; the'current whichwould pass through the photo cells 'when lightr-was concentrated "on themthrough the film-might not be strong enoughto operate the electromagnets referred to above; each photocell could bein an electrical circuitof its own (not-shown in FigJ-l) :leadingthroughe resistance capacity coupllngto the-grid of a valve or system of valves andsthe electrical circuit of the :above-namedsolenoids-would pass iromna high tensionrbattery-to theanode-of each valve associated with' the corresponding photocell.

Thus when light 'falls on;:say;the: photocell I 5, a

current will fiowin the; circuit of the; photocel1-= from its own electrical supplyandithis willpcause a corresponding current to flow fromthethighi tension-battery to passthrbughthevalve'assoe ciated withphotocel1:l5 and-through the circuit shown in Figure 1 as passing through photocell? l5. 'A similar'arrangement would apply in connection'with photocell l4. Thus'whenlight falls alternately on the photo. cells 14 and I5, alternate movements of the armature ll would be caused bythe? circuit from thebatterya Theermature l l in turnco-acts'with the fixed: contacts 5, B connected'in a; circuitrinot shownll'. including known means for moving-therudder of the torpedo to port or starboard according to whether the contact 5 or contact 6 is touched by the armature A sound-on-film recording is made, using the usual methods of sound film production, of the submarine sounds caused by a torpedo approaching under the water. A positive is made of the photographic film so that if a beam of light was projected through it, the series of light fluctuations caused would correspond with the sound impulses which had been used to make the film.

It is preferable to use the varying density method of recording of the sound track and to select a portion of the film where the sound is high pitched, that is, where the series of dark and V light bands are close together. As only a short length of film is used, this is facilitated by the fact that the sound emitted by machinery is recurrent.

The chosen portion of film is made into an endless band by joining the ends together, care being taken that at the junction, the sound on film reproduction will not be thrown out of gear, so that when the film is placed in position on the sprocketsshown in Figure 1 and made to revolve at an appropriate speed, a light concentrated on a minute portion of the film and passing through it will cause a continuous series of light fluctuations corresponding to the sound impulses which had been used to make the film.

Since the film hasrecorded thereon a record of the sound pattern emitted by the target to be attacked, light is able to pass through the film to actuate the photo cells l4, [5 if fluctuations thereof correspond with the recordings on the film, but light signals not synchronising with the sound fluctuations recorded on the film will be prevented from passing through the film;' the sound track on the film thus acts as a lighttrap for light signals not synchronising with the sound record on thesound track.

The film l9 also passes through the gateway I6 and thus controls passage of light from the lamps |2, |3 to the cells I4, l5.

The film is carried on sprockets 6 one of which is driven by a chain 28 from a sprocket 29 and worm and worm wheel 2|. This wheel 2| derives its power from a motor I 8 operating through the clutch diagrammatically shown as comprising a clutch plate 2;, central rod w and expanded end a: which rod passes freely through the 'wheel 2| and a clutch plate y affixed thereto. The wheel 7 2|' is'of the nature of an armature within the range of the electromagnets 20, 20a. When either of these magnets is energised it draws the wheel 2| towards its poles to release the clutch, against the action of springs 22 connected to a part in association with the clutch plate '11 whichnormally pull firmly against it, the clutch plate 11 thereby communicating the drive from the motor l8 through the chain 28 to the film l9.

The film 9 is made to revolve faster than necessary vwhen the light fluctuations of the lamps l2, 13 are in synchronism with the sound track, this being effected by the motor I8.

The apparatus'is adjusted in such a way that thellight caused in the neon lamps when the torpedo' has been discharged towards its target will be of sufiicient strength to penetrate the light spaces of the variable density sound track on the average and to'influence the photo cells in such a way that thecurrent from the battery will cause the electromagnets to act efficiently, it being understood that there would necessarily be a certain amountfof variation in the current released. by thev photo cells. v

When the revolving film reaches the point when its markings correspond with the fluctuations of the lamps I2, l3, the increase of illumination from either or both of thelamps pass through the gate and through the film where it allows most light to pass. The electro-magnets 20, 20a cause the clutch plates 1; to slip and the speed of the wheel 2| slows down, causing the film to revolve slower. If the film speed becomes so slow that it slips out of synchronism with the light fluctuations, then the electromagnets 20, 20a cease to act and the clutch plates cause it to speed up.

The speed of the motor l8 and the strength of the springs 22 may be adjusted so as to ensure the correct amount of slipping of theclutch and maintenance of synchronisation 0f the film W Light thus impinging on the photo cells l4, l5 brings into operation the electromagnets 20, 20a. The guiding mechanism operates as follows:

The intensity of light in the lamps l2-and |3 varies with the intensity of sound received by the respective microphones. If, say the microphone l, is directly facing the target to be attacked, the intensity of light from lamp 2 which the film will allow to pass through to cell M will be at a maximum compared with that from lamp l3 to cell I 5, which will be at a minimum since practically no. sound from the target willbe reaching the microphone 8. The current passing through cell M will therefore actuate the electromagnet I which will cause the armature I! to swing into contact with 4 thus in turn causing the rudder to be moved to steer the torpedo to the right. The increasing sound in microphone 8 and the decreasing sound in microphone 1 will gradually until the light from lamp check this movement, I2 and lamp l3 had an equal action on cell l4 and cell l5 respectively and the torpedo will then be facing its target.

When the torpedo starts on its journey, the 7 sound trap film l9, operated by motor working faster than would be necessary when fluctuations are synchronised, would reach a .stage when its light transmission variations would for an in: stant exactly correspond with the series of incoming sound fluctuations and would permit light to pass through the film. At this stage more light would be passing through the film than under normal conditions and the light would be utilised to set the guiding'mechanism in operation. Simultaneously the sound'trap motor would be declutched and the revolving film would tend to slow down, finally arriving at itsnormal speed.

The microphones being'disposed at the sides of .the nose of the torpedo, a slight deviation of the torpedo will alter the amount of sound one microphone will receive compared with the other.

With a large deviation, the nose of theltorpedo itself would get in the track of the sound waves and cut them 01f. from one microphone. The needle i! would act'like the control of a rudder,

e. g., if it were deviated to the right the movethe rudder byv cause the'tor pedo to turn to the right and if deviated tothe' ment would alter the position of any suitable mechanism so as to let the torpedo would turn to theleft.

An arrangement of the character described above can thus control the direction of motion of the defense torpedo in such a way that it travels practically head-on to an oncoming selected hostile torpedo and may be caused to destroy, damage or deflect it.

Such an arrangement is particularly suitable for a torpedo running at a fixed level or one in which up or down movement was not required, but ordinarily, as is usual in torpedoes, the torpedo would be so made that it would travel freely up or down towards its objective and not at a fixed level.

The invention, though principally intended for use against hostile torpedoes may, by a suitable alteration of the sound trap, be used against other selected sound emitting objectives, e. g. hostile surface or submarine craft or a stationary hostile subaqueous object, provided sound the wave form of which is known is emitted thereby.

I claim:

1. A torpedo or other marine or submarine body or craft embodying at least two microphones disposedto be operated by sound vibrations approaching from difierent directions respectively, means for roducing light rays corresponding in intensity with the intensity of the operation of said individual microphones, light actuated means co-acting with each of said light-producing means, a film having a sound track thereon corresponding with sound vibrations emitted by said target, said film being interposed between said light-producing means and said lightactuated means and means actuated by said latter, means serving to control the direction of movement of said torpedo or craft.

2. A torpedo or other marine or submarine body or craft as claimed in claim 1 wherein said light-actuated means comprise photo-electric cells.

DANIEL MICHAEL ODWYER. 

